Relative growth of larvae of
Pacific pink shrimp Pandalus eous under laboratory conditions
M. Aritaki, K. Hamasaki, K. Saotome-2003
Nippon
Suisan Gakkaishi, 69(1): 65-71 (from
ISI Current Contents)
Abstract:
The relative growth and swimming behavior of larval Pandalus eous were
examined for reared individuals during the zoeal and postlarval stages.
Larval rearing was conducted using a 20 U tank maintained at a mean
temperature of 8.0degreesC, and larvae were fed with diatoms (Thalassiosira
spp.) and Artemia nauplii. Larval development consisted of seven zoeal
stages and metamorphosis to the first postlarval stage (decapodid stage)
occurred after 54 days. Larval characteristics were examined based on
morphological development, swimming behavior, and points of change in
relative growth of body parts to carapace length expressed in terms of
allometric equations. The first and second zoeal stages were a period of
transition during which swimming behavior changed from passive to active.
All body appendages appeared in the third zoeal stage and active swimming
behavior was fully apparent in the fourth zoeal stage. Between the sixth and
seventh zoeal stages, larval behavior changed gradually from pelagic to
benthic. After metamorphosis to the first postlarval stage, larvae became
fully benthic. The points of change in relative growth occurred at two
molting periods, that between the second and third zoeal stages, and that
between the fourth and fifth zoeal stages. These points coincided with the
critical periods at which larval mass mortality ordinarily occurs during
seed production.
(Japan
Sea Farming Assoc., Miyako stn., Miyako Iwate 0270097, Japan, e-mail of K.
Hamasaki: katsuyuki-hainasaki@jasfa.or.jp)